The primary purpose for development of this invention is to provide a cost effective method of minimizing agricultural sprinkler wheel track ruts. It relates to stabilizing soil structure with water soluble polymer. Center-pivot sprinklers and linear movement sprinklers use large wheels to enable movement through an irrigated field. There are generally one or more support towers on these sprinkler systems. Each tower generally has two tires, one trailing the other. Due to the weight of the overhead sprinkler system and the softness of the wet ground the wheel tracks can become deep ruts, occasionally causing the sprinkler system to get stuck.
In the past, irrigators learned to live with the problem. They would purchase special wheels (see U.S. Pat. No. 5,046,785) to prevent them from getting stuck in the deep ruts, or they would fill in the ruts during the irrigation season (see U.S. Pat. Nos. 6,386,792 and 4,909,334). Another option has been to move the sprinkler heads behind the trailing wheel (see U.S. Pat. No. 6,116,527), allowing the wheels to travel on drier ground.
Irrigators have begun using water soluble polymers for soil stabilization. Until now, they have generally been applied to irrigation water for erosion control and to improve water penetration. Liquid polymers are being injected into sprinkler irrigations systems (see U.S. Pat. No. 6,000,625) to stabilize soil structure and improve water penetration. While this method begins to stabilize soil throughout the field, it does not provide enough water soluble polymer in the wheel tracks to reduce rutting. Also, from a cost perspective, water soluble polymer is spread over the entire field instead of only in the wheel tracks.
Granular and solid polymeric products (i.e. blocks, tablets, or gel logs) have been placed in furrows for erosion control and for improving water infiltration during gravity irrigation (see U.S. Pat. No. 5,749,672). However, prior to this invention, solid polymeric products had not been developed or used for stabilizing sprinkler wheel tracks.